NORRISTOWN, Pa. (CBS) — New figures released by a legislative agency in Harrisburg show which counties in the Philadelphia area have the highest numbers of texting while driving violations.

The Center for Rural Pennsylvania found that drivers in Montgomery and Chester counties are more likely to get snagged for using their cell phones to text while driving. The reasons why it’s higher in those two counties is unclear, but the numbers for 2013 show 22 violations for every 100,000 drivers in Chester County and almost 21 violations in Montgomery County. PennDOT’s Brad Rudolph says the law took effect about three years ago.

“The numbers are still pretty new,” he says, “but they have been up and it’s mainly drivers doing their part to put these devices down and just drive.”

The highest rates were found in four rural counties in northcentral Pennsylvania, while AAA Mid-Atlantic reported in March that the city of Philadelphia fell to second in the actual number of texting while driving citations by municipality.